1. Field of the Invention
The present general inventive concept relates to an image bearing structure and a method to detect a defect in the image bearing structure. More particularly, the present general inventive concept relates to an image bearing structure to detect an open or short state of a ring electrode, and a method to detect a defect in the image bearing structure.
2. Description of the Related Art
A ‘direct’ printing refers to a printing operation to form an image by directly applying an image signal onto an image drum, thereby forming a latent image thereon, and developing the latent image. The direct printing does not require devices such as a light exposure unit or electric potential charging unit, which is generally required in an electrophotographic printing, and also provides stable processing. Therefore, the direct printing has constantly been researched.
FIG. 1 illustrates an image forming apparatus employing a conventional image bearing structure.
Referring to FIG. 1, a latent image is formed on the image bearing structure 10, and toner is fed from a toner feed unit 60 and attached onto the image bearing structure 10. The final form of image is formed in a direct printing manner, as some of the toner is separated from the image bearing structure 10 by a magnetic cover 70, while the remaining toner is transferred onto a printing medium.
The above process requires a plurality of ring electrodes to be disposed on a surface of the image bearing structure 10. An arrangement of the ring electrodes may vary according to a desired resolution. For example, approximately 5000 ring electrodes are disposed at regular intervals on the surface of the image drum, in order to achieve resolution of 600 Dpi for an A4 size paper. The 5000 electrodes have to be connected electrically to corresponding control units to form a correct image and to provide reliability to the users. Therefore, electrical connections of the electrodes are inspected periodically, to ensure that no defect such as electrical open or short circuit occurs, as this can cause serious problems such as electric leakage or fire.
Conventionally, detecting devices are installed separately from the image bearing structure to determine whether the electrical connection of all the 5000 or more electrodes is stable. Accordingly, this conventional method requires separate detecting devices and long inspecting hours.